Phase I research demonstrated that the production of a highly differentiated, serum-free, commercially viable cell culture model of the airway epithelium is realistic. Primary, normal human bronchial epithelial cells (NHBE) were expanded in monolayer culture and cryopreserved to provide a large homogenous source of normal NHBE cells. Next, a serum-free differentiation medium was developed which induced the NHBE to form a stratified, differentiated tissue, which exhibited an in vivo-like, mucociliary phenotype. The resultant tissue was characterized in terms of morphology, ultrastructure, viability, and mucin production. In all cases, there was good correspondence between the in vivo and in vitro bronchial tissue. Finally, an economic assessment of the costs involved in producing such tissues showed that such a differentiated airway epithelial product appears to be commercially feasible. Phase II studies will expand on the Phase I results to further develop the three-dimensional, differentiated bronchial epithelial model into an accurate, useful, and scientifically rigorous product. Initial Phase II research will focus on optimizing the differentiation medium. After medium optimization is complete, the tissue will be characterized in terms of the extent of cilia formation, the formation of tight junctions, chemokine/cytokine secretion, surface adhesion molecules, control over mucin secretion, and reproducibility. Finally, the use of the tissue as a screen for agents which are likely to cause occupational asthma, and the utilization of the tissue as a model to study bacterial infection of the bronchia, will be investigated. PROPOSED COMMERCIAL APPLICATION: The proposed research will produce a highly useful tissue culture model of the airway epithelium. Such a model is anticipated to have broad commercial application in assisting companies determine whether their volatile products may cause adverse respiratory reactions. In addition, such an in vitro tissue will provide researchers with a valuable tool in studying various disease states of the respiratory tract and in developing.